Entamoeba histolytica

This parasite can live in the large intestine without causing symptoms. However, the amoeba often produces intestinal pain, fever, and severe diarrhea. The infection may become chronic without proper treatment. The parasite is widely distributed in tropical and subtropical zones. It is estimated that between 40,000 and 100,000 people die each year worldwide. In Japan, about 500 to 1,000 human cases were recorded (as of 2021).